With the adoption of no-till (NT) management, maize is planted into co
oler seed beds than under conventional (CT) management. On clay soils,
reduced yield under NT has been ascribed in part to poor emergence be
cause of low cold tolerance during germination and early seedling elon
gation. This study was conducted to identify a rapid efficient laborat
ory predictor which would select commercially available maize hybrids
with better than average cold tolerance. Experiments were carried out
on 14 hybrids and a well known check, Pride 5, using controlled enviro
nments in germinators to measure time to root and coleoptile germinati
on and time to production of a 1 cm coleoptile at 11 degrees C. Growth
measurements were made over a period of 4 weeks in a growth chamber a
t 12 degrees C day/10 degrees C night and 16 hour days. No correlation
between germination at 25 degrees C and 11 degrees C was found indica
ting that measurements of low temperature tolerance during germination
were not biased by variation in optimum germination at 25 degrees C.
Corn heat unit ratings were not reliable predictors of cold tolerance
but time to production of a 1 cm coleoptile at 11 degrees C was identi
fied as being an efficient predictor.